//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24376 SUBJECT: LIGO/Virgo S190503bf: IceCube Neutrino Search DATE: 19/05/03 19:50:43 GMT FROM: Erik Blaufuss at U. Maryland/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search for track-like muon neutrino events consistent with the sky localization of S190503bf in a time range of 1000 seconds centered on the alert event time (2019-05-03 18:45:44.294 UTC to 2019-05-03 19:02:24.294 UTC) during which IceCube was collecting good quality data. No track-like events are found in spatial coincidence with the 90% spatial containment of S190503bf calculated from the map circulated in the preliminary notice. IceCube's sensitivity to point sources within the location spanned by the 90% spatial containment of S190503bf ranges from 0.227 to 0.821 GeV cm^-2 in a 1000 second time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24377 SUBJECT: LIGO/Virgo S190503bf: Identification of a GW compact binary merger candidate DATE: 19/05/03 20:19:20 GMT FROM: Shaon Ghosh at UWM The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S190503bf during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-05-03 18:54:04.294 UTC (GPS time: 1240944862.294). The candidate was found by the GstLAL [1], CWB [2], MBTAOnline [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S190503bf is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.6e-09 Hz, or about one in 19 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190503bf The classification of the GW signal, in order of descending probability, is BBH (96%), MassGap (3%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, there is strong evidence against the lighter compact object having a mass < 3 solar masses (HasNS: <1%). Using the masses and spins inferred from the signal, there is strong evidence against matter outside the final compact object (HasRemnant: <1%). One skymap is available at this time and can be retrieved from the GraceDB event page: * bayestar.fits.gz, an updated localization generated by BAYESTAR [6], distributed via GCN notice about 36 minutes after the candidate For the bayestar.fits.gz skymap, the 90% credible region is 448 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 421 +/- 105 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Messick et al. PRD 95, 042001 (2017) [2] Klimenko et al. PRD 93, 042004 (2016) [3] Adams et al. CQG 33, 175012 (2016) [4] Nitz et al. PRD 98, 024050 (2018) [5] Qi Chu, PhD Thesis, The University of Western Australia (2017) [6] Singer & Price PRD 93, 024013 (2016) [GCN OPS NOTE(05may19): Per author's request, the redundant "SUBJECT:" string was removed from the SUBJECT-line. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24379 SUBJECT: LIGO/Virgo S190503bf: AGILE MCAL observations DATE: 19/05/03 21:03:47 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi, G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO-Virgo GW event S190503bf at T0 = 2019-05-03 18:54:04 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) data found no data acquisitions related to the event, due to a complete Earth occultation of the S190503bf 90% c.l. localization region. The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24380 SUBJECT: LIGO/Virgo S190503bf: INTEGRAL prompt observation DATE: 19/05/03 21:22:44 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF James Rodi (IAPS-Roma, Italy), Sandro Mereghetti (INAF IASF-Milano, Italy) V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland), A. Coleiro (APC, France) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration report: Using the combination of INTEGRAL all-sky detectors (following Savchenko et al. 2017, A&A 603, A46): SPI/ACS, IBIS/Veto, and IBIS we have performed a search for a prompt gamma-ray counterpart of S190503bf (GCN 24377). At the time of the event (2019-05-03 18:54:04 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 120 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (5.7% of optimal) response of ISGRI, strongly suppressed (28% of optimal) response of IBIS/Veto, and somewhat suppressed (64% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was very stable (excess variance 1.3). We have performed a search for any impulsive events in INTEGRAL SPI- ACS (as described in Savchenko et al. 2012, A&A 541A, 122S), IBIS, and IBIS/Veto data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 2.4e-07 erg/cm^2 for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~2.1e-07 (8.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24382 SUBJECT: LIGO/Virgo S190503bf: AGILE-GRID Observations DATE: 19/05/03 22:24:06 GMT FROM: Giovanni Piano at INAF-IAPS G. Piano, A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Verrecchia (SSDC, and INAF/OAR), M. Cardillo, C. Casentini (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO-Virgo GW event S190503bf at T0 = 2019-05-03 18:54:04.294 (UT), a preliminary analysis of the AGILE Gamma-Ray Imaging Detector (GRID) exposure shows that the S190503bf 90% c.l. localization region (LR) was almost completely occulted by the Earth at T0. We performed a preliminary analysis at different timescales; values of 3-sigma upper limits (UL) in the energy range 50 MeV - 50 GeV are: (1) around 5.7e-7 erg cm^-2 s^-1 for an integration time of 5s, between T0 and T0+5s, with the GRID exposure covering nearly 4% of the LR, observed at off-axis angles between 10 and 15 deg. (2) around 2.8e-7 erg cm^-2 s^-1 for an integration time of 10s, between T0 and T0+10s, with the GRID exposure covering nearly 4% of the LR, observed at off-axis angles between 10 and 15 deg. (3) around 5.5e-8 erg cm^-2 s^-1 for an integration time of 100s, between T0 and T0+100s, with the GRID exposure covering nearly 4% of the LR, observed at off-axis angles between 10 and 30 deg. These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24383 SUBJECT: LIGO/Virgo S190503bf: MAXI/GSC Observations DATE: 19/05/04 00:51:16 GMT FROM: Hitoshi Negoro at Nihon U H. Negoro (Nihon U.), S. Sugita, M. Serino (AGU), M. Sugizaki, N. Kawai (Tokyo Tech), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the LVC trigger S190503bf at 2019-05-03 18:54:04.294 UTC (GCN 24377). At the trigger time of S190503bf, the high-voltage of MAXI/GSC was off, and it was turned on at T0+499 sec (=T0+8.3 min). The first one-orbit (92 min) scan observation with GSC after the event covered 100% of the 90% credible region of the bayestar skymap from 19:45:53 to 20:09:23 UTC (T0+3109 to T0+4519 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 4-10 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24385 SUBJECT: LIGO/Virgo S190503bf: Fermi-GBM Observations DATE: 19/05/04 03:11:32 GMT FROM: C. Michelle Hui at MSFC/Fermi-GBM C.M. Hui and C. A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group For S190503bf and using the initial BAYESTAR skymap, Fermi-GBM was observing 62% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo detection of GW trigger S190503bf (GCN 24377). An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVC localization region is behind the Earth for Fermi, located at RA=73.8, Dec=21.9 with a radius of 67.2 degrees. We therefore set upper limits on impulsive gamma-ray emission considering the 90% credible region of the GW localization not blocked by the Earth. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.1 s: 4.1-4.6 8.6-9.5 27.-28. 1.0 s: 1.2-1.4 2.7-2.9 7.9-8.3 10 s: 0.3-0.4 0.8-0.9 2.5-2.6 Assuming the median luminosity distance of ~421 Mpc from the GW detection, we estimate intrinsic luminosity upper limits of (0.1-1.5) E49 erg/s for the soft template, (0.2-2.8)E49 erg/s for the normal template, and (1.2-14.)E49 erg/s for the hard template over the 1 keV-10 MeV energy range. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24387 SUBJECT: LIGO/Virgo S190503bf: ANTARES neutrino search DATE: 19/05/04 08:54:21 GMT FROM: Damien Dornic at CPPM,France M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite Paris Diderot), M. Colomer (APC/Universite Paris Diderot)), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite Paris Diderot), T. Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES Collaboration: Using on-line data from the ANTARES detector, we have performed a follow-up analysis of the recently reported LIGO/Virgo S190503bf event using the 90% contour of the probability map provided by the GW interferometers at event time. The ANTARES visibility at the time of the alert, together with the 50% and 90% contours of the probability map (initial bayestar map) are shown in https://www.cppm.in2p3.fr/~dornic/events_runo3/S190503bf.png. Considering the location probability provided by the LIGO/Virgo collaborations, there is a 98% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of the alert. No up-going muon neutrino candidate events were recorded in the ANTARES sky during a +/- 500s time-window centered on the time (2019-05-03 18:54:04 UT) and in the 90% contour of the S190503bf event. The expected number of atmospheric background events in the region visible by ANTARES is 2.2e-4 in the +/- 500s time window. An extended search during +/- 1 hour gives no up-going muon neutrino coincidence. The expected number of atmospheric background events in the region visible by ANTARES is 1.6e-3 in this larger time window. ANTARES is the largest undersea neutrino detector, installed in the Mediterranean Sea, and it is primarily sensitive to neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24389 SUBJECT: LIGO/Virgo S190503bf: Insight-HXMT/HE observation DATE: 19/05/04 14:04:15 GMT FROM: QiBin Yi at IHEP, HXMT Q. B. Yi, Q. Luo, C. Cai, S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: Insight-HXMT was taking data normally around the GW trigger time(T0=2019-05-03 18:54:04 UTC). However, at T0 only about 0.01% of the LIGO localization region was covered by the Insight-HXMT without occultation by the Earth. Thus we cannot set upper limit on the impulsive emission for this GW event. Insight-HXMT is the first Chinese space X-ray telescope, which was fundedjointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24390 SUBJECT: LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart DATE: 19/05/04 16:22:00 GMT FROM: Elena Moretti at IFAE,Barcelona E.Moretti (IFAE, Barcelona), M. Axelsson (KTH and Stockholm Univ.), D. Kocevski (NASA/MSFC) and N. Omodei (Stanford Univ.) report on behalf of the Fermi-LAT Collaboration: We have searched data collected by the Fermi Large Area Telescope (LAT) on May 03, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190503bf (GCN 24377). We define "instantaneous coverage" as the integral over the region of the LIGO probability map that is within the LAT field of view at a given a time, and "cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT had instantaneous coverage of ~50% of the LIGO probability at the time of the trigger (T0 = 2019-05-03 18:54:26 UTC), and reached 100% cumulative coverage after ~7 ks. We performed a search for a transient counterpart within the observed region of the 90% contour of the LIGO map in a fixed time window from T0 to T0 + 10 ks. No significant new sources are found. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found. Energy flux upper bounds for the fixed time interval between 100 MeV and 100 GeV for this search vary between 1.5e-10 and 9e-10 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is Elena Moretti ( moretti@ifae.es). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. -- *Institut de Física d'Altes Energies (IFAE) Universitat Autònoma de Barcelona, Edifici Cn 08193 Bellaterra (Barcelona), Spain Tel:+34 931 70 27 10Avís - Aviso - Legal Notice - (LOPD) - http://legal.ifae.es * -- Avís - Aviso - Legal Notice - (LOPD) - http://legal.ifae.es //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24391 SUBJECT: LIGO/Virgo S190503bf: Swift/BAT Counterpart Search DATE: 19/05/04 18:00:39 GMT FROM: Amy Lien at GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), A. A. Breeveld (MSSL-UCL), A. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia(ASDC), S. Emery (UCL-MSSL), P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), D. Hartmann (Clemson U.), J. A. Kennea (PSU), H. A. Krimm (NSF), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), B. Mingo (U. Leicester), J. A. Nousek (PSU), S. R. Oates (Uni. of Warwick), P. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), K. L. Page (U.Leicester), M. Perri (ASDC), J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (PSU), E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: We report the search results in the BAT data within T0 +/- 100 s of the LVC event S190503bf (LIGO/VIRGO Collaboration GCN Circ. 24377), where T0 is the LVC trigger time (2019-05-03T18:54:04.294 UTC). The center of the BAT field of view at T0 is RA = 94.035 deg, DEC = -21.368 deg, ROLL = 293.102 deg. The BAT FOV (>10% partial coding) covers 99.75% of the integrated LVC localization probability, and 99.82% of the galaxy convolved probability (Evans et al. 2016). Within T0 +/- 100 s, no significant detections (signal-to-noise ratio >~ 5 sigma) are found in the BAT raw light curves with time bins of 64 ms, 1 s, and 1.6 s. Note that the short spike around ~T-400s is due to detector noise. Assuming an on-axis (100% coded) short GRB with a typical spectrum in the BAT energy range (i.e., a simple power-law model with a power-law index of -1.32, Lien & Sakamoto et al. 2016), the 5-sigma upper limit in the 1-s binned light curve corresponds to a flux upper limit (15-350 keV) of ~ 6.74 x 10^-8 erg/s/cm^2. Event data are available from T0+17.837 to T0+21.002. Image analysis from the entire event data range and in 15-350 keV shows a marginal detection of 6.049 sigma at (RA, DEC) = (42.0339,-20.9022) deg (following the BAT onboard image trigger threshold, we consider detections below ~ 7 sigma in the image domain to be sub-threshold.). The location is at the edge of the BAT FOV and well outside of the 90% LVC containment region. Also, no significant structure is seen in the mask-weighted light curve at this position. Therefore, we believe that this marginal detection is unlikely to be related to the LVC event, and possibly not astrophysical. Within the LVC 99.5% containment region, the highest significance detection in this image is 4.7 sigma, which is consistent with noise fluctuation that we have seen in BAT images. BAT retains decreased, but significant, sensitivity to rate increases for gamma-ray events outside of its FOV. About 0.25% of the integrated LVC localization probability was outside of the BAT FOV but above the Earth's limb from Swift's location, and the corresponding flux upper limits for this region are within roughly an order of magnitude higher than those within the FOV. The results of the BAT analysis are available at https://swift.gsfc.nasa.gov/results/BATbursts/team_web/S190503bf/web/source.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24396 SUBJECT: LIGO/Virgo S190503bf Global MASTER-Net observations report DATE: 19/05/05 08:34:34 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko (Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University) A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk (Irkutsk State University) V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University, Blagoveschensk) R. Podesta, Carlos Lopez and F. Podesta (Observatorio Astronomico Felix Aguilar (OAFA)) Hugo Levato and Carlos Saffe (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias) D. Buckley, S. Potter, A. Kniazev, M. Kotze (South African Astronomical Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the LIGO/Virgo S190503bf errorbox 82590 sec after trigger time at 2019-05-04 17:50:34 UT, with upper limit up to 17.1 mag. The observations began at zenit distance = 137 deg. The sun altitude is -24.0 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) started inspect of the LIGO/Virgo S190503bf errorbox 1 days 6266 sec after trigger time at 2019-05-04 20:38:30 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenit distance = 144 deg. The sun altitude is -13.0 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the LIGO/Virgo S190503bf errorbox 1 days 13671 sec after trigger time at 2019-05-04 22:41:55 UT, with upper limit up to 17.9 mag. Observations started at twilight. The observations began at zenit distance = 127 deg. The sun altitude is -10.3 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=10299 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 82680 | 2019-05-04 17:50:34 | MASTER-SAAO | ( 6h 40m 57.76s , -53d 55m 35.74s) | C | 180 | 14.4 | 82896 | 2019-05-04 17:54:10 | MASTER-SAAO | ( 6h 24m 00.16s , -51d 56m 39.11s) | C | 180 | 15.3 | 83114 | 2019-05-04 17:57:48 | MASTER-SAAO | ( 6h 15m 02.74s , -53d 56m 50.00s) | C | 180 | 15.6 | 84897 | 2019-05-04 18:27:31 | MASTER-SAAO | ( 4h 23m 21.06s , -37d 30m 09.15s) | C | 180 | 14.9 | 85108 | 2019-05-04 18:31:02 | MASTER-SAAO | ( 4h 23m 20.80s , -37d 30m 09.15s) | C | 180 | 14.3 | 88678 | 2019-05-04 19:30:31 | MASTER-SAAO | ( 6h 36m 26.20s , -51d 58m 31.86s) | C | 180 | 13.3 | 88926 | 2019-05-04 19:34:40 | MASTER-SAAO | ( 6h 14m 54.66s , -53d 59m 26.60s) | C | 180 | 15.7 | 89203 | 2019-05-04 19:39:17 | MASTER-SAAO | ( 6h 14m 21.48s , -53d 59m 51.62s) | C | 180 | 17.1 | 89574 | 2019-05-04 19:45:27 | MASTER-SAAO | ( 6h 27m 28.11s , -53d 59m 20.02s) | C | 180 | 15.5 | 90039 | 2019-05-04 19:53:12 | MASTER-SAAO | ( 5h 57m 53.55s , -52d 0m 37.63s) | C | 180 | 12.5 | 90681 | 2019-05-04 20:03:55 | MASTER-SAAO | ( 6h 27m 58.55s , -53d 59m 43.52s) | C | 180 | 13.5 | 92449 | 2019-05-04 20:33:23 | MASTER-SAAO | ( 6h 34m 02.23s , -55d 59m 38.19s) | C | 180 | 12.4 | 92666 | 2019-05-04 20:37:00 | MASTER-SAAO | ( 6h 48m 21.17s , -55d 59m 23.01s) | C | 180 | 14.0 | 92757 | 2019-05-04 20:38:30 | MASTER-IAC | ( 5h 32m 47.20s , -14d 1m 55.03s) | C | 180 | 16.5 | 92980 | 2019-05-04 20:42:14 | MASTER-IAC | ( 5h 35m 55.25s , -16d 1m 57.68s) | C | 180 | 16.9 | 93207 | 2019-05-04 20:46:01 | MASTER-IAC | ( 5h 35m 55.41s , -16d 2m 23.22s) | C | 180 | 17.3 | 93436 | 2019-05-04 20:49:50 | MASTER-IAC | ( 5h 32m 47.92s , -14d 2m 29.36s) | C | 180 | 16.5 | 93660 | 2019-05-04 20:53:33 | MASTER-IAC | ( 5h 36m 03.47s , -16d 1m 13.51s) | C | 180 | 15.8 | 93788 | 2019-05-04 20:55:42 | MASTER-SAAO | ( 6h 47m 52.16s , -55d 59m 44.47s) | C | 180 | 16.9 | 95830 | 2019-05-04 21:29:44 | MASTER-IAC | ( 8h 31m 42.74s , -45d 56m 14.33s) | C | 180 | 17.7 | 96010 | 2019-05-04 21:29:44 | MASTER-IAC | ( 8h 31m 42.75s , -45d 56m 14.09s) | C | 540 | 18.0 | Coadd 95830 | 2019-05-04 21:29:44 | MASTER-IAC | ( 8h 19m 57.11s , -45d 54m 07.94s) | C | 180 | 16.9 | 96055 | 2019-05-04 21:33:29 | MASTER-IAC | ( 8h 19m 56.70s , -45d 54m 39.34s) | C | 180 | 17.0 | 96055 | 2019-05-04 21:33:29 | MASTER-IAC | ( 8h 31m 42.69s , -45d 56m 40.68s) | C | 180 | 17.8 | 96572 | 2019-05-04 21:42:06 | MASTER-IAC | ( 8h 31m 43.70s , -45d 56m 28.07s) | C | 180 | 17.7 | 100161 | 2019-05-04 22:41:55 | MASTER-OAFA | ( 4h 19m 04.60s , -38d 2m 11.68s) | C | 180 | 12.7 | 100428 | 2019-05-04 22:46:21 | MASTER-OAFA | ( 4h 19m 03.23s , -38d 2m 10.99s) | C | 180 | 12.5 | 100699 | 2019-05-04 22:50:52 | MASTER-OAFA | ( 6h 41m 54.52s , -53d 57m 40.36s) | C | 180 | 15.7 | 100984 | 2019-05-04 22:55:38 | MASTER-OAFA | ( 4h 19m 08.30s , -38d 3m 12.29s) | C | 180 | 15.9 | 101208 | 2019-05-04 22:59:22 | MASTER-OAFA | ( 4h 29m 16.22s , -38d 2m 49.46s) | C | 180 | 16.4 | 101443 | 2019-05-04 23:03:17 | MASTER-OAFA | ( 6h 42m 04.11s , -53d 58m 42.67s) | C | 180 | 17.0 | 101669 | 2019-05-04 23:07:02 | MASTER-OAFA | ( 6h 55m 41.32s , -53d 58m 23.22s) | C | 180 | 17.3 | 101899 | 2019-05-04 23:10:52 | MASTER-OAFA | ( 4h 29m 18.16s , -38d 2m 15.91s) | C | 180 | 17.3 | 102134 | 2019-05-04 23:14:47 | MASTER-OAFA | ( 6h 23m 51.01s , -51d 59m 11.64s) | C | 180 | 17.4 | 102359 | 2019-05-04 23:18:33 | MASTER-OAFA | ( 6h 55m 41.42s , -53d 58m 17.36s) | C | 180 | 17.7 | 102586 | 2019-05-04 23:22:20 | MASTER-OAFA | ( 6h 14m 51.01s , -53d 59m 08.46s) | C | 180 | 13.6 | 102817 | 2019-05-04 23:26:10 | MASTER-OAFA | ( 6h 23m 51.00s , -51d 59m 13.60s) | C | 180 | 16.8 | 103041 | 2019-05-04 23:29:55 | MASTER-OAFA | ( 6h 36m 51.72s , -51d 58m 51.37s) | C | 180 | 17.3 | 103712 | 2019-05-04 23:41:06 | MASTER-OAFA | ( 6h 36m 50.32s , -51d 58m 50.25s) | C | 180 | 13.1 | 106897 | 2019-05-05 00:34:10 | MASTER-OAFA | ( 6h 5m 24.81s , -55d 59m 22.82s) | C | 180 | 13.9 | 108021 | 2019-05-05 00:52:55 | MASTER-OAFA | ( 6h 17m 02.59s , -47d 59m 23.90s) | C | 180 | 14.4 | 108700 | 2019-05-05 01:04:14 | MASTER-OAFA | ( 6h 17m 00.99s , -47d 59m 22.31s) | C | 180 | 15.1 | 108923 | 2019-05-05 01:07:57 | MASTER-OAFA | ( 6h 28m 59.65s , -47d 59m 02.52s) | C | 180 | 15.4 | 109605 | 2019-05-05 01:19:19 | MASTER-OAFA | ( 6h 28m 59.25s , -47d 59m 02.07s) | C | 180 | 15.3 | 111409 | 2019-05-05 01:49:23 | MASTER-OAFA | ( 5h 55m 06.24s , -49d 59m 38.79s) | C | 180 | 12.2 | 113328 | 2019-05-05 02:21:21 | MASTER-OAFA | ( 6h 49m 45.25s , -51d 58m 07.67s) | C | 180 | 15.1 | 113826 | 2019-05-05 02:29:39 | MASTER-OAFA | ( 6h 25m 33.42s , -57d 58m 45.37s) | C | 180 | 16.0 | 114140 | 2019-05-05 02:34:53 | MASTER-OAFA | ( 6h 49m 46.09s , -51d 58m 30.61s) | C | 180 | 14.6 | 114397 | 2019-05-05 02:39:11 | MASTER-OAFA | ( 7h 2m 45.33s , -51d 57m 49.33s) | C | 180 | 14.4 | 114663 | 2019-05-05 02:43:36 | MASTER-OAFA | ( 6h 25m 31.18s , -57d 58m 44.52s) | C | 180 | 14.6 | 114921 | 2019-05-05 02:47:54 | MASTER-OAFA | ( 6h 40m 36.92s , -57d 58m 40.93s) | C | 180 | 16.4 | 115194 | 2019-05-05 02:52:27 | MASTER-OAFA | ( 7h 2m 44.63s , -51d 57m 48.92s) | C | 180 | 15.4 | 115696 | 2019-05-05 03:00:49 | MASTER-OAFA | ( 6h 40m 37.49s , -57d 58m 37.60s) | C | 180 | 16.6 | 115924 | 2019-05-05 03:04:37 | MASTER-OAFA | ( 6h 26m 04.92s , -45d 58m 44.23s) | C | 180 | 16.6 | 116149 | 2019-05-05 03:08:22 | MASTER-OAFA | ( 6h 40m 50.29s , -47d 58m 40.42s) | C | 180 | 14.9 | 116374 | 2019-05-05 03:12:07 | MASTER-OAFA | ( 6h 52m 48.85s , -47d 58m 21.77s) | C | 180 | 15.5 | 116599 | 2019-05-05 03:15:52 | MASTER-OAFA | ( 6h 26m 05.53s , -45d 58m 40.56s) | C | 180 | 16.7 | 116823 | 2019-05-05 03:19:36 | MASTER-OAFA | ( 6h 37m 35.40s , -45d 58m 23.41s) | C | 180 | 16.7 | 117046 | 2019-05-05 03:23:19 | MASTER-OAFA | ( 6h 52m 46.96s , -47d 58m 19.88s) | C | 180 | 16.6 | 117277 | 2019-05-05 03:27:10 | MASTER-OAFA | ( 8h 3m 35.65s , -53d 56m 11.58s) | C | 180 | 17.9 | 117505 | 2019-05-05 03:30:59 | MASTER-OAFA | ( 6h 37m 34.68s , -45d 58m 21.28s) | C | 180 | 16.9 | 117734 | 2019-05-05 03:34:47 | MASTER-OAFA | ( 7h 41m 41.11s , -51d 57m 04.90s) | C | 180 | 15.9 | 117914 | 2019-05-05 03:34:47 | MASTER-OAFA | ( 7h 41m 41.10s , -51d 57m 04.93s) | C | 540 | 16.5 | Coadd 117957 | 2019-05-05 03:38:31 | MASTER-OAFA | ( 8h 3m 35.03s , -53d 56m 13.48s) | C | 180 | 17.3 | 118181 | 2019-05-05 03:42:14 | MASTER-OAFA | ( 8h 17m 09.35s , -53d 55m 55.49s) | C | 180 | 17.4 | 118406 | 2019-05-05 03:45:59 | MASTER-OAFA | ( 7h 41m 39.41s , -51d 57m 06.14s) | C | 180 | 16.0 | 118776 | 2019-05-05 03:52:09 | MASTER-OAFA | ( 7h 41m 38.25s , -51d 57m 06.29s) | C | 180 | 16.0 | 119157 | 2019-05-05 03:58:31 | MASTER-OAFA | ( 8h 17m 09.88s , -53d 55m 53.94s) | C | 180 | 17.0 | 119604 | 2019-05-05 04:05:58 | MASTER-OAFA | ( 8h 7m 37.82s , -51d 56m 28.54s) | C | 180 | 13.6 | 119832 | 2019-05-05 04:09:45 | MASTER-OAFA | ( 8h 30m 43.79s , -53d 55m 37.38s) | C | 180 | 16.1 | 120063 | 2019-05-05 04:13:36 | MASTER-OAFA | ( 6h 55m 38.68s , -57d 58m 07.89s) | C | 180 | 16.5 | 120289 | 2019-05-05 04:17:23 | MASTER-OAFA | ( 8h 7m 37.20s , -51d 56m 10.51s) | C | 180 | 15.8 | 120514 | 2019-05-05 04:21:08 | MASTER-OAFA | ( 8h 20m 34.77s , -51d 55m 53.62s) | C | 180 | 14.6 | 120739 | 2019-05-05 04:24:52 | MASTER-OAFA | ( 8h 30m 43.36s , -53d 55m 59.02s) | C | 180 | 16.5 | 120962 | 2019-05-05 04:28:35 | MASTER-OAFA | ( 8h 44m 20.26s , -53d 55m 43.28s) | C | 180 | 16.7 | 121444 | 2019-05-05 04:36:38 | MASTER-OAFA | ( 7h 10m 43.96s , -57d 57m 47.99s) | C | 180 | 17.1 | 121676 | 2019-05-05 04:40:30 | MASTER-OAFA | ( 8h 20m 34.81s , -51d 56m 29.25s) | C | 180 | 15.8 | 121900 | 2019-05-05 04:44:13 | MASTER-OAFA | ( 8h 44m 20.02s , -53d 55m 56.71s) | C | 180 | 16.3 | 122428 | 2019-05-05 04:53:02 | MASTER-OAFA | ( 7h 47m 01.50s , -49d 56m 54.98s) | C | 180 | 16.6 | 122911 | 2019-05-05 05:01:04 | MASTER-OAFA | ( 8h 33m 35.42s , -51d 56m 21.10s) | C | 180 | 16.7 | 123091 | 2019-05-05 05:01:04 | MASTER-OAFA | ( 8h 33m 35.42s , -51d 56m 21.17s) | C | 540 | 17.1 | Coadd 123485 | 2019-05-05 05:10:39 | MASTER-OAFA | ( 7h 59m 27.30s , -49d 56m 57.11s) | C | 180 | 16.8 | 123717 | 2019-05-05 05:14:31 | MASTER-OAFA | ( 8h 33m 33.96s , -51d 55m 47.50s) | C | 180 | 16.6 | 123942 | 2019-05-05 05:18:15 | MASTER-OAFA | ( 8h 33m 32.16s , -51d 55m 43.84s) | C | 180 | 16.7 | 124167 | 2019-05-05 05:22:01 | MASTER-OAFA | ( 8h 46m 30.68s , -51d 55m 47.10s) | C | 180 | 16.5 | 124347 | 2019-05-05 05:22:01 | MASTER-OAFA | ( 8h 46m 30.69s , -51d 55m 47.08s) | C | 540 | 16.9 | Coadd 124747 | 2019-05-05 05:31:40 | MASTER-OAFA | ( 8h 28m 14.52s , -55d 55m 59.98s) | C | 180 | 16.7 | 124976 | 2019-05-05 05:35:30 | MASTER-OAFA | ( 8h 46m 30.36s , -51d 55m 33.03s) | C | 180 | 16.3 | 125201 | 2019-05-05 05:39:15 | MASTER-OAFA | ( 8h 46m 29.67s , -51d 55m 48.11s) | C | 180 | 16.6 | 125762 | 2019-05-05 05:48:35 | MASTER-OAFA | ( 8h 28m 12.10s , -55d 55m 54.84s) | C | 180 | 17.1 | 126289 | 2019-05-05 05:57:23 | MASTER-OAFA | ( 8h 42m 30.39s , -55d 56m 01.15s) | C | 180 | 17.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24403 SUBJECT: LIGO/Virgo S190503bf: CALET Observations DATE: 19/05/06 10:18:19 GMT FROM: Valentin Pal'shin at AGU M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), T. Tamura, Y. Shimizu (Kanagawa U), N. Cannady (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) and the CALET collaboration: At the trigger time of the compact binary merger candidate S190503bf, T0=2019-05-03 18:54:04.294 UTC (The LIGO Scientific Collaboration and Virgo Collaboration, GCN Circ. 24377), the high-voltage of the CALET Gamma-ray Burst Monitor (CGBM) detectors were off (from T0-23 min to T0+8 min). The CALET Calorimeter (CAL) was operating in high energy trigger mode at the trigger time of S190503bf. Using the CAL data, we have searched for gamma-ray events in the 10-100 GeV band within the time interval T0 +/- 60 sec and found no candidates. The 90% upper limit of CAL is 4.2x10^-5 erg/cm2/s (10-100 GeV) when the summed LIGO-Virgo probability reaches 10%. The CAL FOV was centered at RA=169.0 deg, Dec=-45.5 deg at T0. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24415 SUBJECT: LIGO/Virgo S190503bf: AstroSat CZTI upper limits DATE: 19/05/07 07:54:16 GMT FROM: Varun Bhalerao at Indian Inst of Tech A. Anumarlapudi (IITB), Aarthy E. (PRL), P. Ghumatkar (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: We have carried out a search for X-ray candidates in Astrosat CZTI data in a 100 sec window around the trigger time of the BBH merger event S190503bf (UTC 2019-05-03 18:54:04, GraceDB event). CZTI is a coded aperture mask instrument that has considerable effective area for about 29% of the entire sky, but is also sensitive to brighter transients from the entire sky. At the time of merger, Astrosat's nominal pointing is (RA=270.41, DEC=-20.569), which is 107 deg away from the maximum probability location. At the time of merger event, the highest probability point of the localisation is entering into the earth occultation cone, with an Earth-satellite-transient angle ~ 67 deg which is close to the Earth's limb. In a time interval of 50 sec around the event, 38% of sky locations in the 90% probability region for the event is visible in the satellite's frame and the remaining 62% is occulted by the Earth. CZTI data were de-trended to remove orbit-wise background variation. We then searched data from three of the four independent, identical quadrants to look for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in count rates were estimated by using data from 10 (+-5) neighbouring orbits. We selected confidence levels such that the probability of a false trigger in a 1000 sec window is 10^-4. We do not find evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV. We convert our count rates into flux by assuming that the source spectrum is a power law with alpha = -1.0. We use a detailed mass model of the satellite to calculate the instrument response for every htm grid point that fall in 90% LIGO localization region and calculate flux limit in that direction. We get the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean of flux limits: 0.1 s: flux limit= 6.0 e-7 ergs/cm^2/s 1.0 s: flux limit= 1.8 e-6 ergs/cm^2/s 10.0 s: flux limit= 3.5 e-6 ergs/cm^2/s We note that AstroSat was in the South Atlantic Anomaly at the instants of S190425z and S190426c, hence no data are available for those events. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24431 SUBJECT: LIGO/Virgo S190503bf: TAROT-GRANDMA observation report DATE: 19/05/09 09:03:24 GMT FROM: Nelson Christensen at Obs.de la Cote dAzur,Nice C. Stachie (Artemis), C. Thoene (HETH/IAA-CSIC), X. Zhang (THU), Z. Vidadi (Shao), M. Boer (Artemis), N. Christensen (Artemis), L. Eymar (Artemis), A. Klotz (IRAP), K. Noysena (Artemis, IRAP), S. Antier (APC), S. Basa (LAM), D. Corre (LAL), M. Coughlin (Caltech), D.Coward (OzGrav-UWA), J.G. Ducoin (LAL), B. Gendre (OzGrav-UWA), P. Hello (LAL), C. Lachaud (APC), N. Leroy (LAL), D. Turpin (NAOC), X. Wang (THU), report on behalf of the TAROT network and GRANDMA collaboration. We performed tiled observations of LIGO/Virgo S190503bf event with the TAROT-Chili telescope operating in clear filter. The observation started on 05/03/19 23:16:23 UTC which corresponds approximately to 263 minutes after the GW trigger time. We performed the following tiled observations : +------------+------------+---------+---------+---------+ | TStart     | TEnd       | RA      | DEC     |   Proba | | [UTC]      | [UTC]      | [deg]   | [deg]   |     [%] | |------------+------------+---------+---------+---------| | 2019-05-03 | 2019-05-04 | 97.627  | -53.636 |     2.3 | | 23:16:23   | 03:34:12   |         |         |         | | 2019-05-03 | 2019-05-04 | 95.575  | -55.455 |     2.2 | | 23:23:12   | 03:41:00   |         |         |         | | 2019-05-03 | 2019-05-04 | 94.576  | -53.636 |     3   | | 23:30:01   | 03:59:07   |         |         |         | | 2019-05-03 | 2019-05-04 | 96.585  | -51.818 |     2.6 | | 23:42:26   | 03:14:59   |         |         |         | | 2019-05-03 | 2019-05-03 | 95.625  | -50     |     2.5 | | 23:49:15   | 23:55:45   |         |         |         | | 2019-05-03 | 2019-05-04 | 92.812  | -50     |     2.4 | | 23:56:03   | 03:27:25   |         |         |         | | 2019-05-04 | 2019-05-04 | 93.659  | -51.818 |     2.9 | | 00:21:32   | 03:08:10   |         |         |         | +------------+------------+---------+---------+---------+ The Probability refers to the 2D spatial probability of the GW skymap enclosed in a given tile. Each tile is 1.9x1.9 degrees. These observations cover about 17% of the cumulative probability of the skymap. The typical limiting magnitude is 18.0 for a 60.0 s exposure. The coverage map is available at: https://grandma-owncloud.lal.in2p3.fr/index.php/s/9MO62YiDroG6GU6 According to our data analysis, no serious optical transient candidates were found. GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of robotic telescopes connected all over the world with both photometry and spectrometry capabilities for Time- domain Astronomy (https://grandma.lal.in2p3.fr/). Details on the TAROT telescopes are available on the GRANDMA web pages or on http://tarot.obs-hp.fr/ This circular is citable. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24545 SUBJECT: LIGO/Virgo S190503bf: Gaia Photometric Alerts transient candidate DATE: 19/05/14 22:00:27 GMT FROM: Zuzanna Kostrzewa-Rutkowska at SRON Z. Kostrzewa-Rutkowska (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker (SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient candidate within the probability skymap of S190503bf (the LIGO Scientific Collaboration and the Virgo Collaboration, GCN 24377): --------------------------------------------------------------------------- Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL --------------------------------------------------------------------------- Gaia19bsu AT2019ffb 2019-05-09T23:55:04 69.58702 -27.52734 18.72 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bsu/ --------------------------------------------------------------------------- Acknowledgements: This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ acknowledge support from the European Research Council under ERC Consolidator Grant agreement no 647208. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24682 SUBJECT: LIGO/Virgo S190503bf: Gaia Photometric Alerts transient candidate DATE: 19/05/30 20:30:59 GMT FROM: Zuzanna Kostrzewa-Rutkowska at SRON Z. Kostrzewa-Rutkowska (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker (SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient candidate within the probability skymap of S190503bf (the LIGO Scientific Collaboration and the Virgo Collaboration, GCN 24377): --------------------------------------------------------------------------- Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL --------------------------------------------------------------------------- Gaia19byp AT2019gbc 2019-05-04T04:26:31 96.29730 -46.09287 20.94 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19byp/ --------------------------------------------------------------------------- Acknowledgements: This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ acknowledge support from the European Research Council under ERC Consolidator Grant agreement no 647208.